package com.rainbow.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;


public class MD5Util {

	public static final Logger LOG = LoggerFactory.getLogger(MD5Util.class);
	private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };
	
	/**
	* MD5 加密  
	* @param str 字符串
	* @return 返回加密后的字符串
	*/
	public static String getMD5Str(String str) {
		MessageDigest messageDigest = null;
		
		try {
			messageDigest = MessageDigest.getInstance("MD5");
			
			messageDigest.reset();
			
			messageDigest.update(str.getBytes("UTF-8"));
		} catch (NoSuchAlgorithmException e) {
			LOG.info("getMD5Str error", e);
		} catch (UnsupportedEncodingException e) {
			LOG.info("getMD5Str erro", e);
		}
		
		byte[] byteArray = messageDigest.digest();
		
		StringBuffer md5StrBuff = new StringBuffer();
		
		for (int i = 0; i < byteArray.length; i++) {
			if (Integer.toHexString(0xFF & byteArray[i]).length() == 1)
				md5StrBuff.append("0").append(Integer.toHexString(0xFF & byteArray[i]));
			else
				md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));
		}
		
		return md5StrBuff.toString();
	}
	
	public static String MD5Encode(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname))
				resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
			else
				resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
		} catch (Exception exception) {
		}
		return resultString;
	}
	
	private static String byteArrayToHexString(byte b[]) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++)
			resultSb.append(byteToHexString(b[i]));

		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n += 256;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	
	
	/**
	 * chck password
	 * @param newStr
	 *        no encrypt password
	 * @param oldMD5Str
	 * 
	 * @return
	 */
	public final static boolean checkMD5(String newStr, String oldMD5Str) {
		String temp = getMD5Str(newStr);
		LOG.info("MD5Util.checkMD5 sign:"+temp);
		if (temp != null && temp.equals(oldMD5Str)) {
			return true;
		} else {
			return false;
		}
	}
}
